Linux Tips

Linux Check Thermal Throttling

- by John Britto - Leave a Comment - 2 min read
Quick Linux Tip #62:

Question: My laptop is slow - is it thermal throttling?

Try: watch -n 1 'grep MHz /proc/cpuinfo | sort -u; sensors | grep -E "Core|Package"'

Info: CPU clock speeds can drop when temperatures reach thermal limits. sensors displays live hardware temperatures, while the CPU frequency output shows current clock speeds. Low MHz under heavy load combined with high temperatures can indicate thermal throttling.

Examples:

  • $ cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq  # Check current CPU frequencies
  • $ sensors | grep -i temp  # Filter temperature sensor readings
  • $ cpupower frequency-info  # Inspect CPU frequency and governor settings

Note: Install hardware monitoring with sudo apt install lm-sensors and run sudo sensors-detect if needed. Modern CPUs can reduce their clock speed when temperatures approach thermal limits to protect the hardware. Look for sustained high temperatures together with reduced CPU frequency rather than relying on temperature alone.




LinuxTeck.com 
linuxteck@ubuntu:~$ watch -n 1 'grep MHz /proc/cpuinfo | sort -u; sensors | grep -E "Core|Package"'
Every 1.0s: grep MHz /proc/cpuinfo | sort -u; sensors | grep Core

cpu MHz         : 800.123
cpu MHz         : 1234.567
cpu MHz         : 2345.678
cpu MHz         : 3456.789
Core 0:         +76.0°C  (high = +80.0°C, crit = +100.0°C)
Core 1:         +75.0°C  (high = +80.0°C, crit = +100.0°C)
Core 2:         +77.0°C  (high = +80.0°C, crit = +100.0°C)
Core 3:         +78.0°C  (high = +80.0°C, crit = +100.0°C)

linuxteck@ubuntu:~$

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About John Britto

John Britto Founder & Chief-Editor @LinuxTeck. A Computer Geek and Linux Intellectual having more than 20+ years of experience in Linux and Open Source technologies.

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